Observational Constraints On Submillimeter Dust Opacity
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Infrared extinction maps and submillimeter dust continuum maps are powerful probes of the density structure in the envelope of star-forming cores. We make a direct comparison between infrared and submillimeter dust continuum observations of the low-mass Class 0 core, B335, to constrain the ratio of submillimeter to infrared opacity (kappa(smm)/kappa(ir)) and the submillimeter opacity power-law index (kappa alpha lambda(-beta)). Using the average value of theoretical dust opacity models at 2.2 mu m, we constrain the dust opacity at 850 and 450 mu m. Using new dust continuum models based upon the broken power-law density structure derived from interferometric observations of B335 and the infall model derived from molecular line observations of B335, we find that the opacity ratios are kappa(850)/kappa(2.2) = (3.21-4.80)(-0.30)(+0.44) x 10(-4) and kappa(450)/kappa(2.2) = (12.8-24.8)(-1.3)(+2.4) x 10(-4)with a submillimeter opacity power-law index of beta(smm) = (2.18-2.58)(-0.30)(+0.30). The range of quoted values is determined from the uncertainty in the physical model for B335. For an average 2.2 mu m opacity of 3800 +/- 700 cm(2) g(-1), we find a dust opacity at 850 and 450 mu m of kappa(850) = (1.18-1.77)(-0.24)(+0.36) and kappa(450) = (4.72-9.13)(-0.98)(+1.9) cm(2) g(-1) of dust. These opacities are from (0.65-0.97) kappa(OH5)(850) of the widely used theoretical opacities of Ossenkopf and Henning for coagulated ice grains with thin mantles at 850 mu m.